/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | foam-extend: Open Source CFD
   \\    /   O peration     | Version:     4.1
    \\  /    A nd           | Web:         http://www.foam-extend.org
     \\/     M anipulation  | For copyright notice see file Copyright
-------------------------------------------------------------------------------
License
	This file is part of foam-extend.

	foam-extend is free software: you can redistribute it and/or modify it
	under the terms of the GNU General Public License as published by the
	Free Software Foundation, either version 3 of the License, or (at your
	option) any later version.

	foam-extend is distributed in the hope that it will be useful, but
	WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
	General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with foam-extend.  If not, see <http://www.gnu.org/licenses/>.

Class
	Foam::SHA1

Description
	Functions to compute SHA1 message digest according to the NIST
	specification FIPS-180-1.

	Adapted from the gnulib implementation.

See also
	Foam::SHA1Digest

SourceFiles
	SHA1I.H
	SHA1.C

\*---------------------------------------------------------------------------*/

#ifndef SHA1_H
#define SHA1_H

#include <string>
#include <cstddef>

#include "int.H"
#include "SHA1Digest.H"

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

namespace Foam
{

// Forward declaration of classes
class Ostream;

// Forward declaration of friend functions and operators
class SHA1;
class SHA1Digest;
Ostream& operator<<(Ostream&, const SHA1&);



class SHA1
{
	// Private data

		//- Track if the hashsum has been finalized (added count, etc)
		bool finalized_;

		//- The hash sums
		uint32_t hashsumA_;
		uint32_t hashsumB_;
		uint32_t hashsumC_;
		uint32_t hashsumD_;
		uint32_t hashsumE_;

		//- The total number processed, saved as 64-bit
		uint32_t bufTotal_[2];

		//- The number of elements pending in the buffer
		uint32_t bufLen_;

		//- The input processing buffer
		uint32_t buffer_[32];

	// Private Member Functions

		//- Swap bytes from internal to network (big-endian) order
		static inline uint32_t swapBytes(uint32_t);

		//- Copy the 4-byte value into the memory location pointed to by *dst.
		//  If the architecture allows unaligned access this is equivalent to
		//  *(uint32_t *) cp = val
		static inline void set_uint32(unsigned char *cp, uint32_t);

		//- Process data block-wise, LEN must be a multiple of 64!
		void processBlock(const void *data, size_t len);

		//- Process for the next LEN bytes, LEN need not be a multiple of 64.
		void processBytes(const void *data, size_t len);

		//- Calculate current digest from appended data.
		void calcDigest(SHA1Digest&) const;

public:

	// Constructors

		//- Construct null
		inline SHA1();

		//- Construct and append initial std::string
		explicit inline SHA1(const std::string&);

		//- Construct and append initial string
		explicit inline SHA1(const char*);

	// Member Functions

		//- Reset the hashed data before appending more
		void clear();

		//- Append data for processing
		inline SHA1& append(const char* data, size_t len);

		//- Append string for processing
		inline SHA1& append(const std::string&);

		//- Append string for processing
		inline SHA1& append(const char* str);

		//- Finalized the calculations (normally not needed directly).
		//  Returns false if no bytes were passed for processing
		bool finalize();

		//- Calculate current digest from appended data.
		SHA1Digest digest() const;


	// Member Operators

		//- Equality operator, compares %digests
		inline bool operator==(const SHA1&) const;

		//- Compare %digest
		inline bool operator==(const SHA1Digest&) const;

		//- Compare %digest to (40-byte) text representation (eg, from sha1sum)
		//  An %empty string is equivalent to
		//  "0000000000000000000000000000000000000000"
		inline bool operator==(const std::string& hexdigits) const;

		//- Compare %digest to (40-byte) text representation (eg, from sha1sum)
		//  A %null or %empty string is equivalent to
		//  "0000000000000000000000000000000000000000"
		inline bool operator==(const char* hexdigits) const;


		//- Inequality operator, compares %digests
		inline bool operator!=(const SHA1&) const;

		//- Inequality operator, compare %digest
		inline bool operator!=(const SHA1Digest&) const;

		//- Inequality operator, compares %digests
		inline bool operator!=(const std::string& hexdigits) const;

		//- Inequality operator, compare %digest
		inline bool operator!=(const char* hexdigits) const;


		//- Convert to a SHA1Digest,
		//  calculate current %digest from appended data
		inline operator SHA1Digest() const;


	// Friend Operators

		//- Output the %digest
		inline friend Ostream& operator<<(Ostream&, const SHA1&);

};


// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

} // End namespace Foam

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

#include "SHA1I.H"

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

#endif

// ************************************************************************* //
